1. Brain Damage & Neurodegeneration Flashcards
(25 cards)
Are the following terms interchangeable?
- brain damage
- brain disease
- brain injury
no: however they have strong physiological connections
brain disease - longer term
brain injury - e.g hitting head
What is congenital vs acquired brain injury?
congenital: genetic factors that affect neurodevelopment, pre-natal or birth related trauma
acquired: includes silly things we do, can either be traumatic or non-traumatic
What is non-traumatic vs traumatic brain injury?
non traumatic: not sudden, includes a range of conditions e.g strokes, infections, tumours, hypoxia/anoxia
traumatic: sudden
What are the two main causes of a stroke?
- cerebral haemorrhage
- cerebral ischaemia
How does cerebral haemorrhage lead to a stroke?
- artery in brain bursts, causing bleeding in surrounding tissue
- blood shouldn’t come into contact with neutral tissue as it is essentially toxic
- often results from an aneurism: if spotted before rupture it can sometimes be treated
How does cerebral ischaemia lead to a stroke?
- blood vessel blockage, leading to an interruption of blood supply to part of the brain
- leads to a lack of oxygen/glucose leads to excitotoxicity and neuronal cell death
What is closed vs open brain injury?
closed: no penetration of the skull
- brain floats in cerebrospinal fluid (cushion)
- damage can be diffuse and widespread
open: skull doesn’t remain intact
- objects penetrate skull and enter brain
- bone fragments can also damage brain tissue
- damage can be localised, but other complications e.g bleeding can lead to wider damage
What are examples of brain disease?
Neurodegenerative:
- Alzheimer’s
- Parkinson’s
Other:
- epilepsy
- infections
cancer
What is Parkinson’s disease?
- idiopathic: no single cause with no cure
- relatively common
- movement disorder: involuntary tremors, less muscle power
What are the symptoms of Parkinson’s disease?
- insufficiency of movement
- bradykinesia: very slow movements
- akinesia: no movement
- increased muscle tone (rigidity)
- resting tremor
- shuffling gait and flexed posture
- mask like expressions
How is dopamine associated with Parkinson’s disease?
- lack of dopamine in the nigrostriatal dopamine pathway found in the basil ganglia
- 80% of brains dopamine is found in the basil ganglia
- degeneration of dopaminergic neurons within the substantia nigra
How is the basil ganglia associated with Parkinson’s disease?
- inhibits motor output
- should let winning motivation take control: doesn’t happen in Parkinson’s as is initiated by dopamine
- motor output is inhibited: muscles and movement
How can Parkinson’s be treated by enabling the basil ganglia to be off sometimes?
- replace loss of dopamine by…
- levo dopamince
- apomorphine
- deprenyl
- cannabis: dopamine agonist
can’t just give dopamine as it doesn’t cross the BBB
How can Parkinson’s be treated using surgical approaches?
- lesion: surgically damage the problem structures of the basil ganglia to mess with the activity levels
- deep brain stimulation: electrical stimulation of the basil ganglia, inhibiting output
What is dementia vs Alzheimer’s?
dementia = generic term of memory disorders, personality changes and impaired reasoning
alzheimer’s = a disease that causes dementia, accounts for 2/3 cases of dementia
How does a brain with severe alzheimer’s compare to a ‘healthy’ brain?
- shrinkage
- enlarged ventricles
What are the symptoms of Alzheimer’s?
- main symptom is memory loss
- selective decline in memory
- deficits in attention and personality changes
- intermediate stages: confusion, anxiety, irritability
- final stages: swallowing and bladder control
How does the neuropathology in AD differ?
- build up of amyloid plaques (protein): accumulates compromising the neurons environment
- come from APP molecule (amyloid precursor protein)
What is the genetic risk factors of AD?
APP is found on chromosome 21 (downs syndrome)
- genetic forms of AD appear to have early onset
- usually mutations of the APP gene
apoE (Apolipoprotein E)
- risk or protective factor
- 3 common alleles
- E4 = bad
- E2 = good
-
What are neurofibrillary tangles (Tau)?
- neurons that have sticks: called microtubules
- part of the cytoskeleton which keeps a cells shape
- made up of MAPs (microtubule associated proteins)
- Tau is a MAP
- Tau gets into a muddle and tangles leading to clumps
- this happens inside neurons
How have animal models helped us understand AD?
- genetically modify animals: display AD
How can AD be treated?
not a cure but treating tau, amyloid or apoE can reduce symptoms
- treatment therefore targets loss of neurons that produce/release the NT acetylcholine, which is important for normal cognitive function especially memory
What is cholinesterase AchE?
- enzyme that breaks down acetylcholine
- prevents it to act on neuron s
- inhibit AchE ajd you prolong the effect of acetylcholine on the neurons
